Adjustable trigger spring



1959 J. w. NORMAN ADJUSTABLE TRIGGER SPRING Filed May 28, 1957 United States Patent 2,871,604 ADJUSTABLE TRIGGER SPRING Joseph W. Norman, Springfield, Massi, assignor to Smith .and Wesson Inc., Springfield, Mass., a corporation of Massachusetts Application May 28, 1957, Serial No. 662,194

7 Claims. (Cl. 42-69) In the firearm art it is often desirable to adjust the effective tension of the trigger spring to vary the so called trigger action from a very light pull to a firm pull. Objects of the present invention are to provide 'means for adjusting the trigger action which is simple and economical to construct, which can be adjusted quickly and easily, which does not change the distance the trigger rnust be pulled to fire, and which is durable and reliable in use.

According to the present invention the firearm comprises a spring for yieldingly holding the trigger in normal position independently of the sear with a transmitter between the spring and trigger for transmitting the spring force to the trigger, the transmitter being adjustable transversely of the trigger axis tovary the distance between the axis and the effective point of action of the spring on the trigger, thereby to vary the trigger action, Preferably one end of the spring is anchored on the frame of the firearm and the other end bears on the transmitter at a predetermined point of the transmitter.

More specifically the spring comprises a leaf spring extending lengthwise 'of the path of adjustment of the transmitter and the transmitter is slidably mounted on the trigger between the trigger and its pivot pin immediately below the pivot pin, the transmitter having a series of recesses in its upper side to receive the pivot pin in different adjusted positions respectively, whereby the transmitter may be shifted from one position to the other-by removing the pivot pin. While the leaf spring is preferably round in cross-section it may have any desired crosssectional shape.

For the purpose of illustration a typical embodiment of the invention is shown in the accompanying drawings in which Fig. 1 is a vertical longitudinal section of a portion of a firearm;

Figs. 2 and 3 are similar views showing the aforesaid transmitter in different adjusted'positions;

Fig. 4 is a section on line 44 of Fig. 1; and

Fig. 5 is an isometric view of the transmitter.

The particular embodiment of the invention chosen for the purpose of illustration comprises a frame F, a barrel B, a trigger T and a trigger bar S. The barrel B tatrrted Feb- 3, 1.959

claimed in my copending application Ser. No. 662,170,

filed on even date herewith. The trigger is pivotallyv mounted on the frame by means of a pin 15 and has an upstanding arm 16 for actuating the trigger bar.

According to the present invention the upper end of the trigger is provided with a longitudinal slot 17 to provide a guide way for the transmitter 18, on the upper side of which is a series of recesses v19 shaped to fit the trigger pivot pin so that, by removing the pin, the transmitter may be shifted to any one of various positions as shown in Figs. 1, 2 and 3. The rear end of the transmitter is provided with an upstanding lug 21 provided with a, longitudinal groove 22 to receive the, free end of the spring 23 which is mounted on the aforesaid pin 4.

With the transmitter in the rearward position shown in Fig. 3 the distance between the pin 15 and the lug 2,1 is long so that the spring exerts a strong action on the trigger. With the transmitter shifted to the forward position shown in Fig. 2 the distance between the pin 15 and lug 21 is short so that the effective action of the spring on the trigger is light. And with the transmitter in the intermediate position shown in Fig. l the spring has an intermediate action. By partially removing the pin 15 the transmitter may be shifted to a different position.

It should be understood that the present disclosure is for the purpose of illustration only and that this invention includes all modifications and equivalents which fall within the scope of the appended claims.

I claim:

1. A firearm comprising a frame, a trigger mounted on the frame to swing about an axis between normal and firing positions, a sear actuated by the trigger, a leaf spring for yieldingly holding the trigger in normal position independently of the sear, the spring extending transversely of said axis, a transmitter for transmitting the spring force to the trigger, the spring bearing on the transmitter and the transmitter being adjustable lengthwise of said spring to vary the distance between the axis and the effective point of action of said spring on the trigger, thereby to vary the trigger action.

2. A firearm comprising a frame, a trigger mounted on the frame to swing about an axis between normal and firing positions, a leaf spring for yieldingly holding the trigger in normal position, the spring extending transversely of said axis, between the trigger and spring a has a depending lug l'which fits under a shoulder 2 on the frame and which has a recess 3 in its rear side. Pivotally mounted on a pin 4 is a lock 6 which swings into the recess 3. The lock is held in locking position by means of a plunger 7, spring 8 and a pin 9, the head of the pin bearing on a nose 11 of the trigger guard 12 which is pivotally mounted on the frame at 13. When the trigger guard is in the normal position shown in Fig. 12 the nose 11 compresses the spring 8 to hold the lock 6 in locking position. However when the guard 12 is swung clockwise about the pin 13 to open-position the head of the pin 9 is retracted by spring 8. into the recess 14 of the trigger guard, thereby relieving pressure on the lock 6 so that the barrel B may be lifted from the frame. This barrel-lock construction is described and transmitter for transmitting the spring force to the trigger, the spring having one end anchored on the frame and the other end bearing on the transmitter and the transmitter being adjustable lengthwise of said spring to vary the distance between the axis and the efiective point of action of said spring on the trigger, thereby to vary the trigger action.

3. A firearm comprising a frame, a trigger mounted on the frame to swing about an axis between normal and firing positions, a leaf spring for yieldingly holding the trigger in normal position, the spring extending transversely of said axis, between the trigger and spring a transmitter for transmitting the spring force to the trigger, the spring having one end anchored on the frame and the other end bearing on the transmitter at a predetermined point and the transmitter being adjustable lengthwise of said spring to vary the distance between the axis and said point, thereby to vary the trigger action.

4. A firearm comprising a frame, a trigger mounted on the frame to swing about an axis between normal and firing positions, on the trigger a transmitter having movement along a path extending transversely of said axis, a leaf spring extending lengthwise of said path, the spring having one end anchored on the frame and the other end bearing on the transmitter, whereby said movement varies the distance between'the axis and the efiective point of action of said spring on the trigger to vary the trigger action.

5. A firearm comprising a frame, a pivot pin detach: ably mounted on the frame, a ftrigger mounted on the pin to swing between normal and firing positions, a spring for yieldingly holding thetriggerin normal position, between the trigger and spring a transmitter for transmitting the spring force to the trigger, the transmitter being adjustable transversely of said pin to vary the distance between the axis and the effective point of action of said spring on the trigger, the transmitter being disposed be tween said pin and trigger and having a series of recesses to receive the pin in different adjusted positions respectively. v

6. A firearm comprising a frame, a pivot pin detachably mounted on the frame, a trigger mounted on the pin to swing between normal and firing positions, on the trigger a transmitter which is adjustable along a path extending transversely of said pin, a leaf spring extending lengthwise of said path, the spring having one end anchored on the frame and the other end bearing on the transmitter, the transmitter being disposed betweensaid aa'rgeoa,

pin and trigger and having a series of recesses to receive 'the'pin in diiferent'adjusted positions respectively.

7. A firearm comprising a frame having side walls with a space therebetween, a pivot pin extending through one wall, thence across said space and thence into the other wall, a trigger having its upper end mounted on the pin to swing between normal anclfil'ing positions, said upper end having a guideway extending transversely of the pin immediately below the pin, adjustably sliding in said guideway a transmitter having a series of recesses in its upper side to receive the pin in different adjusted positions respectively, and a leaf spring mounted on said frame approximately in line with said guideway with free end bearing on the end of said transmitter.

References Cited in the file of this patent UNITED STATES PATENTS 

